Non-standard
This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.
Summary
The :-moz-first-node CSS pseudo-class represents any element that is the first child node of some other element. It differs from :first-child because it does not match a first child element with (non-whitespace) text before it.
Any white space at the start of an element is ignored for the determination of :-moz-first-node.
Syntax
span:-moz-first-node { style properties }
Example
CSS
span:-moz-first-node {
background-color: lime;
}
HTML
<div> <span>:-moz-first-node</span> <span>:-moz-last-node</span> </div>